1. Field of the Invention
The present invention relates to a process for threading a material web, e.g., a paper or cardboard web, onto a reel, such as onto an empty or partially wound reel, and a winding machine for threading a material web, e.g., a paper or cardboard web, onto a reel, such as onto an empty or partially wound reel.
2. Discussion of Background Information
Threading of a material web onto a reel is necessary at the beginning of a new winding process with a new, not yet wound reel (xe2x80x9cempty reelxe2x80x9d) or for continuing an already begun winding process after an unintentional or deliberate tearing of the web with a partially wound reel.
It is generally known for the leader strip (e.g., the edge strip of the material web), which comes from a machine for producing or refining a material web and which is guided over a part of the circumference of the support drum, to be threaded immediately onto the reel that forms a nip with the support drum. Only then is the leader strip widened out to the fall material web width. However, the immediate threading of the leader strip onto the reel produces a so-called xe2x80x9cwinding carrotxe2x80x9d with an uneven distribution of the web tension at least in the winding core. Consequently, there is the disadvantage that when the material web is unwound again, the part of the material web that was initially wound on should be discarded as waste. It can also occur, for example, after a stoppage of the production or refining machines, that the material web does not initially have the desired quality and/or production features. In this instance, it is undesirable to wind on an unmarketable part of the material web, instead it should be immediately discarded as waste.
In order to prevent the formation of a xe2x80x9cwinding carrotxe2x80x9d and in order to thread the material web onto the reel only after fulfillment of the desired quality and/or production features, as is also generally known, the leader strip is guided over a part of the circumference of the support drum preceding the reel and is supplied to a waste receptacle (xe2x80x9cpulperxe2x80x9d). Various waste receptacles are known from a number of published documents for example, from commonly owned European Patent No. EP 0 664 267 B1, from the commonly owned unpublished German Patent Application No. DE 197 44 505.5, and from the special edition of xe2x80x9cWochenblatt fur Papierfabrikationxe2x80x9d [Paper Manufacturing Weekly] 123, 1995, No. 4, p. 5. After the leader strip has widened out by being continuously conveyed into the waste receptacle, the incoming material web, which is now fill width, is cut and only then is it threaded onto the reel.
The problem that arises in a process of this kind is that the leader strip or the material web has the tendency to thread itself onto the reel in an undesirable way before being cut (xe2x80x9cself-threadingxe2x80x9d). The tendency of the leader strip or the material web to self thread is influenced by various factors, for example, the nip geometry, the surface form, or the percentage of open areas, the reference hardness, the nip force, and the paper properties. In addition, this problem occurs to a greater extent at high web speeds.
Therefore, attempts have already been made to solve this problem, e.g., as disclosed in the European Patent EP 0 658 504 B1, by forming the support drum preceding the reel as a suction drum. In this regard, a vacuum is produced in the drum, which acts on the material web via corresponding openings in the drum and holds the material web against the drum. A self-threading of the material web onto the reel can in fact be largely prevented. In this way, the vacuum in the support drum impedes the removal of the web in order to convey it into the waste receptacle.
Furthermore, the commonly owned unpublished German Patent Application DE 198 48 816.5 proposes a winding machine for winding a material web onto a reel, in which the material web, supplied by an inlet roll, is guided in conjunction with a perforated support belt over a support drum that can be supplied with suction and a nip is formed between the support drum and the reel. After the support drum, the support belt is guided over an outlet roll, which is disposed in the vicinity of a waste pulper. The leader end of the material web or the entire material web is discarded into the pulper before being subsequently threaded onto the reel. Furthermore, the support drum, which is provided with a perforated jacket and/or with circumference grooves, is externally supplied with suction in the part of its circumference that is not wound around by the perforated support belt and the material web. While this device can also prevent a self-threading of the material web onto the reel, the perforated support belt is subject to wear and must consequently be replaced at certain time intervals. Also, the provision of suction to the support drum, which is expensive to manufacture with its perforated jacket and/or circumference grooves, involves increased operating costs.
Furthermore, reference is also made to the commonly owned unpublished German Patent Application DE 198 48 806.8 with regard to the prior art. This patent application discloses a process for threading a material web onto a reel in which the beginning of the material web to be threaded is wound around a drum preceding the reel and, before being threaded onto the reel, is supplied to a preparation station, such as a waste pulper. In this connection, before being threaded onto the reel, the material web is kept away from the reel via blower air. A device for carrying out the process is also disclosed, which has a blower bar disposed lateral to the web travel direction, having at least one outlet opening for the blower air, a device for conveying blower air to the blower bar and a control device for controlling the introduction of blower air. While this process and this device can also prevent a self-threading of the material web onto the reel to a great extent, the demand for blower air involves increased investment costs and high ongoing operating costs for the disclosed device.
The present invention provides a process of the type generally discussed above in which the leader strip or the material web is initially conveyed into the waste receptacle in a reliable and controlled manner and in which self-threading of the leader strip or the material web onto the reel, independent of its current position, is substantially prevented. Moreover, the process does not impede the removal of the web from the support drum preceding the reel. The present invention also provides a suitable device for carrying out the process.
The process of the instant invention provides for threading a material web, e.g., a paper or cardboard web, onto a reel, such as an empty or partially wound reel. In particular, the process includes conveying the leader strip over a part of the circumference of the support drum and is then conveying the leader strip through an effective region of a guide device in a direction of a waste receptacle. The leader strip is then widened out to a desired width of the material web. Then, the reel is placed against the support drum, forming a nip between the support drum and the reel. Finally, the material web is cut and the winding of the material web onto the reel to form a wound roll begins.
The above-described process for threading a material web onto a reel, in particular an empty or partially wound reel, can be repeated with each threading of the material web.
A first additional embodiment of the invention provides that, before the leader strip is conveyed to the support drum, the reel is positioned such that a distance of at least approximately 1 mm is provided or maintained between the support drum and the reel. As a result, the leader strip or the material web can be effectively prevented from threading itself onto the reel.
Another embodiment of the invention provides for the effective region to be a contactless region, for example, that includes at least one air flow or at least one water jet. This results in the advantage that no wear occurs due to possible contact between the leader strip or the material web and the device for carrying out the process.
Another embodiment of the invention provides for the effective region to be a contact region, for example, that includes at least one roll or at least one guide belt. This makes it possible for the leader strip or the material web to be conveyed in a controlled manner through the device for carrying out the process.
Another embodiment of the invention provides for the effective region to be formed to act on one side of the leader strip or the material web. This one-sided action produces the advantage that the device for carrying out the process can be embodied in an inexpensive and efficient manner.
In a preferred embodiment of the invention, the effective region can be formed to act on both sides of the leader strip or the material web. This assures a symmetrical and functionally reliable guidance of the leader strip or the material web.
Another embodiment of the invention provides for the effective region to be embodied in different planes on the leader strip or the material web. The planes are oriented perpendicularly to the movement direction of the leader strip or the material web. This results in the leader strip or the material web being guided in a functionally reliable manner over a longer distance.
Preferably, the at least two planes of the effective region that act on both sides of the leader strip or the material web can be arranged offset from one another. This results in the advantage that the deliberate deflection of the leader strip or the material web permits a controlled guidance.
In a particular embodiment of the invention, the leader strip or the material web can be removed from the support drum by a bladed doctor and/or air doctor. In the past, these types of doctors have turned out to be reasonably priced and very reliable with regard to their function. Furthermore, the removal of the leader strip or the material web can occur by producing an overpressure zone in the support drum, which is provided with bores. This overpressure zone in the support drum provides the advantage that there is no element which contacts the outer surface of the support drum to remove the leader strip or the material web, which would have an abrasive action on the outer surface.
There is another advantageous embodiment of the invention when the widening out of the leader strip to a desired width of the material web occurs via a point cutter. This results in the advantage that the cutting process on the leader strip can be carried out with extremely high precision with regard to cutting quality and the like.
A particularly advantageous embodiment of the invention provides for the desired width of the material web to be the entire web width. This makes it possible for a winding that is even across the width of the reel to take place right from the start and to have a uniform diameter increase at the beginning of the winding of the material web into a wound roll on the reel. Thus, the formation of a so-called xe2x80x9cwinding carrotxe2x80x9d can be prevented.
According to another embodiment of the invention, the cutting of the material web takes place passively and/or actively. The passive cutting can take place, for example, through self cutting by the formation of a loop, the active cutting can take place, for example, via a gooseneck, an IBS belt, or a water jet since all of the abovementioned types are distinguished by high reliability, precision, and cost advantages. The active devices for cutting the material web are part of the prior art and are disclosed in, e.g., European Patent Application EP 0 089 304 A1, International Patent Publication No. WO 92/06913, and commonly owned unpublished German Patent Application DE 198 48 810.6, the disclosures of which are expressly incorporated by reference herein in their entireties.
Preferably, the cutting of the material web occurs only after it fulfills at least one desired quality feature and/or production feature. Desired quality features of the material web include, for example, the surface roughness, the shrikage cross-direction profile, and the fiber orientation, whereas desired production features of the material web include, for example, the web speed, the web width, or the production quantity.
Another advantageous embodiment of the invention provides that, before the leader strip is conveyed to the support drum, at least one pressing element is placed against the support drum, e.g., in the vicinity of the path of travel of the leader strip over the support drum, along with the formation of an effective region, for example, a press nip, a press surface, or a blower zone, between the support drum and the pressing element. This achieves the advantage that self-threading of the leader strip or the material web onto the reel, independent of its current position, can be substantially prevented without impeding the removal of the web from the support drum preceding the reel. With regard to other process aspects for the placement of the pressing element against the support drum, reference is made to the commonly owned unpublished German Patent Application 199 07 550.6, the disclosure of which is expressly incorporated by reference herein in its entirety.
Another embodiment of the invention provides for the pressing element to be moved away from the support drum after the beginning of the winding of the material web onto the reel, which forms the wound roll. This results in maintaining the drive power for the support drum at minimal values that assure the operation and, furthermore, the surface wear both on the support drum and on the pressing element can be reduced due to the nonexistence of an effective region.
A winding machine is also provided in accordance with the features of the instant invention. In particular, the winding machine includes at least one guide device for the material web, which is located between the support drum and the waste receptacle. In this manner, the leader strip or the material web is reliably guided into the waste receptacle.
A first embodiment of the invention provides for the guide device to be disposed immediately before the waste receptacle. This achieves the advantage that the leader strip or the material web is reliably guided into the waste receptacle.
In another embodiment of the invention, the guide device can have a width of approximately 1000 mm, preferably of approximately 750 mm, cross-wise (lateral) to the movement direction of the leader strip. This width can be completely sufficient to prevent a self-threading of the leader strip or the material web. Moreover, a pressing element can be provided to hold the leader strip or material web against the support drum. The manufacturing costs of the pressing element can be related to the preferable width of the web, which can be significantly less than the machine width. In addition, the ongoing operating costs for the pressing element are lower.
It may furthermore be advantageous for the guide device to extend across the entire width of the material web. This advantage may particularly come into play if the basis weight of the material web has values over approximately 80 g/m2. This embodiment then assures that the xe2x80x9cheavyxe2x80x9d material web is guided across the entire width.
It may also advantageous for the guide device to be formed as a roll pair, e.g., as a pair of segmented rolls that are offset in relation to each other and with suitable surface qualities. The segmentation of the rolls produces advantages with regard to friction and strength. Preferably, one roll is embodied as a driven roll. This can lead to an extremely slight possibility of surface friction between the leader strip or the material web and the guide device.
It may also advantageous for the guide device to be formed as a roll pair with at least one perforated roll that is provided with suction. This embodiment makes it possible for the leader strip or the material web to be reliably conveyed into the waste receptacle by the action of adhesive forces in the guide device. It can also be advantageous if the one roll is perforated and provided with suction and the other roll is embodied with a rubber cover. As a result, in addition to the adhesive forces, frictional forces are also produced, making the guidance of the leader strip or the material web even more reliable and effective.
In another embodiment, the guide device can be formed as at least two driven guide belts. Through the structural embodiment of the guide belts with a guide length of approximately 100 to 500 mm, preferably from approximately 200 to 300 mm, and a guide width of approximately 50 to 100 mm, preferably from approximately 70 to 80 mm, the functionally reliable and low-abrasion guidance of the leader strip or the material web through the guide device and into the waste receptacle is achieved. It is also advantageous for the leader strip or the material web to be guided not only in a nip or in a short region, but in a guide segment that has a sufficient guide length. Preferably, a number of guide belts disposed next to one another with a spacing of approximately 20 to 50 mm, preferably approximately 25 to 40 mm, can be used, which can, in turn, be disposed offset in relation to the opposing guide belts, i.e., in the gaps between them. The use of a number of guide belts reduces the belt costs and permits a wear-induced replacement of individual belts. The offset arrangement may result in an even more reliable and effective guidance of the leader strip or the material web.
Another embodiment of the invention provides for the guide device to be embodied as a guidance system that is flowed through by a fluid, and the guidance system can be provided with outlet openings such that the fluid escapes in the direction of the movement direction of the leader strip or the material web, which finally comes into contact with the leader strip or the material web. The above-described embodiment of the guidance system produces a guide device that functions in an abrasion-free manner, which in turn assures a reliable guidance of the leader strip or the material web. In another embodiment, the guidance system is attached on both sides of the leader strip or the material web, which permits an approximately symmetrical guidance. Advantageously, the outlet openings of the guidance system can be positioned in different planes that act cross-wise to the movement direction of the leader strip or the material web. As a result, the guidance of the leader strip or the material web is permitted along a longer guide length with a minimum number of outlet openings. In another embodiment of the invention, the outlet angle of the outlet openings of the guidance system can be adjusted, resulting in the advantage that the forces acting on the leader strip or the material web can be optimized. Advantageously, air or water is used as the fluid flowing through the guidance system. Both fluids assure the functional reliability of the guidance system at justifiable costs when there is an additional adjustability of the pressure of the fluid flowing through the guidance system.
One advantageous embodiment of the invention provides for the guide device to be embodied as a guide surface that is formed by an endless belt that travels between two rolls and is acted upon by a vacuum on a side facing the guide surface. The guide surface produces the advantage that the leader strip or the material web can be reliably and effectively conveyed into the waste receptacle with low investment and operating costs. Preferably, at least one roll is driven, which permits the operating speed to be exactly controlled and optimized.
In another embodiment, the devices that produce the vacuum or overpressure share the common trait that the vacuum or overpressure that is produced can be adjusted. As a result, the operating costs can be optimized with a view to functional reliability.
In a further embodiment of the invention, the guide device can be formed as at least one doctor that acts on the support drum and is provided with at least one blower nozzle which exerts a pressure on the leader strip or the material web in its movement direction. This achieves the advantage that the at least one doctor can remove the leader strip or the material web perfectly from the support drum and the at least one blower nozzle assures the reliable transport of the leader strip or the material web into the waste receptacle, i.e., the functional reliability of the guide device and the runnability of the winding machine of the paper or cardboard machine are assured. Furthermore, the advantage arises that no additional unit has to be built into the winding machine since as a rule, there is a doctor that acts on the support drum. According to the invention, this pre-existing doctor is merely modified.
In another embodiment of the invention, the doctor can have a width of approximately 1000 mm, preferably of approximately 750 mm, cross-wise to the movement direction of the leader strip. This width may be sufficient to prevent a self-threading of the leader strip or the material web. This preferable width, which is also significantly less than the machine width, also permits the manufacturing costs of the doctor to be effectively embodied. In addition, the ongoing operating costs for the doctor are lower.
It is also advantageous for the doctor to extend across the entire width of the material web. This advantage particularly comes into play when the basis weight of the material web has values of over approximately 80 g/m2. This embodiment then assures that the xe2x80x9cheavyxe2x80x9d material web is guided across the entire width.
With regard to the operation of the doctor, it may also be advantageous for it to have a large number of blower nozzles distributed along its length which, in another embodiment of the invention, may be divided into at least two sections that can be acted on by different pressures. This achieves the fact that the doctor, which functions as a guide device, can best fulfill the demands placed on it. Thus, during the treading of the material web by the leader strip, pressure can be exerted on only the section contacted by the leader strip, which in turn results in cost savings and an increase in the process reliability. The pressure acting here generally assumes a value between approximately 1 and 5 bar, preferably between approximately 1.5 and 3 bar. It is to be understood that the sections also have different section widths that preferably lie between approximately 0.7 and 1.5 m. Naturally, the number of blower nozzles per section can also be varied, with 3 to 10 blower nozzles, preferably 4 to 8 blower nozzles, being present in each section.
Another advantageous embodiment of the invention provides for the winding machine to have at least one pressing element that can be placed against the support drum. This achieves the advantage that a self-threading of the leader strip or the material web onto the reel, independent of its current position, can be substantially prevented without impeding the removal of the web from the support drum preceding the reel. With regard to the embodiment of the pressing element, reference is made to the commonly owned unpublished German Patent Application No. 199 07 550.6, which has been expressly incorporated by reference herein in its entirety.
It is to be understood that the above-mentioned features of the invention and those as yet unexplained can be used, not only in the combination indicated, but also in other combinations or by themselves without departing from the scope of the invention.
The present invention is directed to a process for threading a material web onto a reel. The process includes guiding a leader strip of the material web over at least a part of a circumference of a support drum, guiding the leader strip through an effective region of a guide device toward a waste receptacle, widening the leader strip to a desired width of the material web, placing a reel against the support drum, thereby forming a nip, cutting the material web, and winding the material web onto the reel, thereby forming a wound roll.
According to a feature of the instant invention, the reel can include one of an empty reel and a partially wound reel. Further, the material web can include one of a paper and a cardboard web.
In accordance with another feature of the invention, before the leader strip is conveyed to the support drum, the reel may be positioned at a radial distance of at least approximately 1 mm from the support drum.
According to still another feature of the present invention, the effective region can include a contactless region including at least one of at least one air current and at least one water jet. Alternatively, the effective region can include a contact region including at least one of at least one roll and at least one guide belt.
In accordance with a further aspect of the instant invention, the effective region can be arranged to act on only one side of one of the leader strip and the material web.
According to a still further aspect of the invention, the effective region may be arranged to act on both sides of one of the leader strip and the material web.
Further, the effective region may be arranged between n at least two different planes, which are substantially perpendicular to a movement direction of one of the leader strip and the material web. The effective region between the at least two different planes can act on both sides the one of the leader strip and the material web. The two different planes can offset from each other in the movement direction.
According to still another aspect of the instant invention, the process can further include removing the leader strip from the support drum with doctor. The doctor can include least one of a bladed doctor and an air doctor.
In accordance with another aspect of the present invention, the process can further include removing the leader strip from the support drum with an overpressure zone located within the support drum. The support drum can include bores.
In accordance with a further feature of the invention, the widening out of the leader strip to a desired width of the material web can be performed by a point cutter. Further, the desired width of the material web is the entire web width.
Moreover, the cutting of the material web can occur at least one of passively and actively. The passive cutting may include self-cutting by the formation of a loop, and the active cutting may include a gooseneck, an IBS belt, or a water jet.
In accordance with a still further feature of the invention, the cutting of the material web may occur after the material web fulfills at least one of at least one desired quality feature and production feature. The at least one quality feature of the material web can include at least one surface roughness, shrinkage cross-direction profile, and fiber orientation. Further, the at least one production feature of the material web can include at least one of web speed, web width, and production quantity.
Before the leader strip is conveyed to the support drum, the process further can also include moving at least one pressing element against a surface of the support drum. In this manner, the leader strip can be further conveyed between the support drum and the pressing element. In a vicinity of a path of travel of the leader strip over the support drum the effective region is formed as one of a press nip, a press surface, and a blower zone. Further, after the beginning of the winding of the material web onto the reel to form a wound roll, the process may also include moving the pressing element away from the support drum.
The present invention is directed to an apparatus for threading a material web onto a reel. The apparatus includes a support drum adapted to be at least partially wound around by at least a leader strip of the material web, one of a reel and a wound roll positionable against said support drum to form a nip during a winding process, a waste receptacle positioned after the support drum in a web travel direction, and at least one guide device positioned between the support drum and the waste receptacle.
In accordance with a feature of the invention, the reel can include one of an empty reel and a partially wound reel. Further, the material web can be one of a paper and a cardboard web.
According to another aspect of the instant invention, the at least one guide device can be positioned immediately preceding the waste receptacle.
In accordance with an aspect of the present invention, the at least one guide device can have a width of approximately 1000 mm cross-wise to the web travel direction. Further, the at least one guide device can have a width of approximately 750 mm cross-wise to the web travel direction.
According to still another aspect of the invention, the at least one guide device can extend across an entire width of the material web.
In accordance with a further feature of the instant invention, the at least one guide device can include at least one roll pair. The at least one roll pair may include a segmented pair of rolls that is arranged offset relative to each other having a suitable surface quality. At least one roll of the at least one roll pair can include a driven roll.
According to a still further feature of the invention, the at least one guide device can include a roll pair in which at least one roll of the roll pair is a perforated roll adapted to be acted upon by a vacuum. The other of the roll pair can include a rubberized roll.
The at least one guide device may include at least two driven guide belts. The at least one guide belt may have a guide length of between approximately 100 to 500 mm. Further, the at least one guide belt can have a guide length of between approximately 200 to 300 mm. Moreover, the at least one guide belt may have a guide width of between approximately 50 to 100 mm, and preferably between approximately 70 to 80 mm. The at least two belts can be arranged on opposite sides of one of the leader strip and the material web, and each of the at least two belts may include a plurality of adjacent guide belts. A distance between adjacent guide belts is between approximately 20 to 50 mm, and preferably between approximately 25 to 40 mm. The adjacent guide belts can be positionally offset to the adjacent guide belts positioned on the other side of the one of the leader strip and the material web.
In accordance with another feature of the present invention, the at least one guide device can include a guidance system arranged for a fluid to flow therethrough. The guidance system may include outlet openings through which the fluid escapes in the web travel direction. The fluid can be adapted to contact one of the leader strip and the material web. The guidance system may be positioned on both sides of the one of the leader strip and the material web. The outlet openings of the guidance system may be located in different planes oriented substantially perpendicular to the web travel direction. The outlet openings of the guidance system may be adjustable to selectable outlet angles. Further, the fluid can be water. Moreover, the fluid can be air. Still further, a pressure of the fluid flowing through the guidance system is adjustable.
The at least one guide device can include a guide surface formed by an endless belt guided over two rolls. The guide surface, which is adapted to be oriented toward one of the leader strip and the material web, may be acted upon by a vacuum. At least one of the two rolls can be driven. Further, the vacuum may be adjustable.
Moreover, the at least one guide device can include at least one doctor positioned to acts on the support drum. The doctor can include at least one blower nozzle adapted to exerts a pressure on one of the leader strip and the material web. The doctor may have a width of approximately 1000 mm cross-wise to the web travel direction, and preferably approximately 750 mm. The doctor may extend across an entire width of the material web. The doctor can further include a plurality of blower nozzles distributed along its length cross-wise to the web travel direction. The plurality of blower nozzles can be divided into at least two sections, and the plurality of blower nozzles in each of the at least two sections may be acted on with different pressures. The pressure can be between approximately 1 and 5 bar, and preferably between approximately 1.5 and 3 bar.
In accordance with yet another feature of the instant invention, at least one pressing element can be adapted to be placed against the support drum.